所以我就研究怎么用php去判断网页是电脑访问还是手机访问，然后再通过去加载不同的css来达到手机和电脑都可以正常的访问的效果。

网站查了很多资料，终于找到了一个合适、比较好用的代码，也希望能给大家一个参考。
复制代码 代码如下:
<?php

function check_wap() {
if (isset($_SERVER['HTTP_VIA'])) return true;
if (isset($_SERVER['HTTP_X_NOKIA_CONNECTION_MODE'])) return true;
if (isset($_SERVER['HTTP_X_UP_CALLING_LINE_ID'])) return true;
if (strpos(strtoupper($_SERVER['HTTP_ACCEPT']),"VND.WAP.WML") > 0) {
// Check whether the browser/gateway says it accepts WML.
$br = "WML";
} else {
$browser = isset($_SERVER['HTTP_USER_AGENT']) ? trim($_SERVER['HTTP_USER_AGENT']) : '';
if(empty($browser)) return true;
$mobile_os_list=array('Google Wireless Transcoder','Windows CE','WindowsCE','Symbian','Android','armv6l','armv5','Mobile','CentOS','mowser','AvantGo','Opera Mobi','J2ME/MIDP','Smartphone','Go.Web','Palm','iPAQ');

$mobile_token_list=array('Profile/MIDP','Configuration/CLDC-','160×160','176×220','240×240','240×320','320×240','UP.Browser','UP.Link','SymbianOS','PalmOS','PocketPC','SonyEricsson','Nokia','BlackBerry','Vodafone','BenQ','Novarra-Vision','Iris','NetFront','HTC_','Xda_','SAMSUNG-SGH','Wapaka','DoCoMo','iPhone','iPod');

$found_mobile=checkSubstrs($mobile_os_list,$browser) ||
checkSubstrs($mobile_token_list,$browser);
if($found_mobile)
$br ="WML";
else $br = "WWW";
}
if($br == "WML") {
return true;
} else {
return false;
}
}

function checkSubstrs($list,$str){
$flag = false;
for($i=0;$i<count($list);$i++){
if(strpos($str,$list[$i]) > 0){
$flag = true;
break;
}
}
return $flag;
}

if(check_wap()){
echo "wap";
}else{
echo "web";
}

?>

小编已经测试过了，是可以识别是电脑访问还是手机访问的。